Method of preparing plastic containers

ABSTRACT

A method is taught for blow-molding a bottle or other container having an integral fluid transfer passage. A preformed member incorporating the passage is inserted in a mold and the parison is blown into contact therewith. The member is designed so that the parison will bridge the inlet opening, stretch into the opening and finally burst under the blowing pressure, thereby opening up communication between the interior of the container and the exterior environment.

United States Patent [191 Holt ' [451 Oct. 22, 1974 METHOD OF PREPARINGPLASTIC CONTAINERS Inventor: William G. Holt, Raynham, Mass.

Hercules Incorporated, Wilmington, Del.

Filed: June 22, 1973 Appl. No.: 372,576

Assignee:

US. Cl. 222/207, 222/383 Int. Cl B65d 35/10 Field of Search 222/207,209, 383, 211

References Cited UNITED STATES PATENTS 3,648,902 3/1972 Humphrey 222/2073,726,442 4/1973 Davidson et al. 222/207 Primary Examiner--Robert B.Reeves Assistant Examiner-Thomas E. Kocovsky Attorney, Agent, orFirm-William S. Alexander [57] ABSTRACT 3 Claims, 9 Drawing FiguresPAIiminumzzraz a SHEUIN 4 ll-III l1 FIG. 2

PAIENIED UB7 2 21974 3 843 O2 5 arm 3 N 4 MIN MUM 7 III I I I I I I I II I I I I I I I I I I I I 25 IIHHHHIIHIHHHHIIIIIIHIHIIIIHH FIG. 7

1 METHOD OF PREPARING PLASTIC CONTAINERS This invention relates to theart of preparing plastic containers incorporating means for effectingcommunication between the interior and exterior thereof through theirwall. In a specific embodiment it relates to a method of blow-molding abottle incorporating a pump assembly including a channel for conductinga liquid from the interior of the bottle through the wall.

There are many occasions when it is desirable to provide a means ofcommunication between the interior of a container and the externalenvironment and a substantial body of art has grown up exemplifyingapproaches to accomplish this end. One important area where there is ause for this type of structure is in incorporating a pump assembly intoa plastic bottle. US. Pat. No. 3,575,949 is illustrative of a goodmethod of accomplishing this purpose and also of the shortcomings of thebest technique known to date. The reference patent deals specificallywith incorporating a pump into a bottle. Since this is an important areain which the invention has considerable use, the invention will be described in detail with respect to a specific embodiment of thisapplication. However, the invention is not so limited as willhereinafter be made apparent.

In the method disclosed in the reference patent, an elongated channeldefining element is placed in a mold and a parison is blow-molded intocontact with the channel defining element. A problem encountered withthe technique as taught in the reference is that the container wallcovers the inlet to the channel defining element, thereby blockingcommunication between the channel and the interior of the container. Itthen becomes necessary to introduce a needle or other puncturing devicethrough the container wall and into the channel, opening upcommunication between the channel and the interior of the container,then rescaling the puncture on the outside of the channel. This methodis less than satisfactory as it involves extra handling and also leavesa point of potential weakness on the wall of the container. 1

It is the object of this invention to eliminate these shortcomings byeffecting communication between the exterior and the interior of thecontainer during the blow-molding step.

Other objects of this invention will become apparent from the followingdescription with reference to the drawing wherein:

FIGS. 1 and 2 are exploded perspective views of a pump assembly to beemployed in carrying out the instant invention.

FIG. 3 is a view of a mold having the pump assembly of FIG. 1 and aparison therein, preparatory to forming a bottle.

FIG. 4 is a view of a blow-molded bottle incorporating the pump assemblyof FIGS. 1 and 2.

FIG. 5 is a view taken along section line 5-5 of FIG. 4.

FIG. 6 is a view along section line 6-6 of FIG. 4 showing the inletchannel as incorporated into a bottle.

FIGS. 7, 8 and 9 depict other structures in which the principles of thisinvention are employed.

Referring to FIGS. 1 and 2, there are illustrated inner and outerexploded views respectively of a pump assembly 10 comprising a preformedchannel defining and support member 12, a flexible valve 14 and a shroud16. The channel defining member includes an elongated wall 11 and a fiatvalve support table 18. Projections 13 and 13' joined at their upperextremity by an arcuate portion 21, extend inwardly from the innersurface of the elongated wall 11 todefine a channel 15 communicatingwith the outersurface of valve support table 18 via opening 20 (FIG. 1)The lower end of channel 15 has an enlarged portion 22 which will bemore fully explained hereinafter. At the upper end of valve supporttable 18 there is an: elongated nozzle pin 26, and an inner and outersealing lip, 17 and 19 respectively, projecting from thesurface of table18.

The flexible valve member 14 includes an annular peripheral 0" ring 28which surrounds and encloses an inner annular ring 30, the two ringsbeing separated by an annular groove 31. The inner annular ring 30 has agreater height than the peripheral annular 0" ring 28 and at its outerextremity it supports valve face plate 32 which, in turn, supports abubble 33. Disposed transversely across the inner annular ring 30 andextending very slightly above the inner extremity thereof are two vaneportions 34 and 35. Collectively, elements 30, 32, 33, 34'and 35 formthree chambers 36, 37 and 38 on the inner surface of member 14. At thetop of chamber 38 is a poppet 39, containing discharge opening 48. Onthe outer surface, the poppet 39 is encircled by sealing ring 23. g

The shroud 16 comprises a flat section 40 having an opening 42 adaptedto receive bubble 33 and a hollow tubular nozzle 44 extending outwardlyfrom the outer surface thereof, and terminating in discharge opening 45.The top part 41 of flat section 40 is undercut slightly to receivesealing ring 23 and contains an opening 43 extending through nozzle 44to the end thereof where it is reduced to the size of discharge opening45. Opening 43 is slightly larger than nozzle pin 26. Flat section 40 issurrounded by an annular raised shoulder 46 and a peripheral annular lip47.

When elements 12, 14 and 16 are assembled, valve 14 is lined up on valvesupport table 18 so that chamber 36 is in communication with channel 15via opening 20 and nozzle pin 26 is inserted in discharge opening 48 andinner sealing ring 17 on table 18 fits into annular groove 31. Shroud 16is placed over the valve 14 with opening 42 fitting over bubble 33 andnozzle pin 26 fitting into opening 43 in nozzle 44. On the inner surfaceof the shroud 16, flat surface 32 of the valve rests against flatsection 40 and sealing ring 23 fits into the undercut top section 41.

With reference to FIG. 3, to incorporate the pump into a bottle, theassembled pump 10 is integrally united with a blow-molded bottle duringthe manufacture thereof. The bottle is blow-molded by extruding aparison 50, clamping a pair of mold halves 52 and 54 about the parisonand expanding the parison to fill the mold in a manner well known to theart. The assembled pump 10 is incorporated with the bottle during theblow-molding operation by inserting the pump 10 into a correspondingcavity in the mold half 54 prior to closing the mold upon the parison.

As it is expanded to fill the mold, the parison bridges over the sidewalls 13 and 13 and seals against the inside surface of the elongatedwall 11 of member 12 to enclose channel 15 as shown in FIG. 5 and FIG.6, and also seals against the surface of plate portion 18 of member 12.The enlarged end 22 of the channel has an arched edge wall 24 which,with the inner surface of wall 11, defines an inlet opening 25 to thechannel 15.

The circumference angle and height of the arched edge wall 24 are soproportioned that when the parison engages and seals against it underblowing pressure, the parison will stretch and enter the opening 25 ofthe inlet channel formed by the arched wall 24 and f1- nally rupture,thereby communicating the interior of the bottle with the channel 15.

When incorporated into a bottle, the pump operates, in principle, asdescribed in US. Pat-No. 3,575,949.

In carrying out the process of the invention as described in thepreceding paragraph, there is an important interrelationship of thedimensions of the inlet opening, the plastic being molded, and thetemperature and pressure at which the molding is being carried out.Since there is, for a selected polymer, a fairly welldefined set oftemperature and pressure conditions under which blow-molding isoptimally carried out, the parameter most readily varied and thus themost critical is the dimension of the inlet opening. If the peripheraldimension of the inlet opening is too small, the portion of the parisonbridging the opening will not stretch. This is illustrated in theembodiment of the pump depicted herein wherein the parison 50 bridgesthe walls 13 and 13' of the channel 15 without stretching. The depth ofthe opening relative to its peripheral dimension is also important sinceenough length must be provided to allow the parison to stretch into thecavity and rupture prior to engaging the rear of the cavity. If theperipheral dimension of the opening is too large, then the parison willeither drape into the cavity behind the edge of the opening and engagethe wall behind without rupturing rather than stretching and rupturing,or it will simply continue to stretch without reaching its elastic limitand not rupture. To the extent that temperature can be varied within theinherent blow-molding limits for the polymer being used, it is importantthat the temperature be above the temperature at which the amount ofmolecular orientation which takes place is enough to prevent rupture ofthe material bridging the opening and below that at which plastic flowtakes place so readily that the polymer sags into the opening withoutstretching or at which, in the case of the embodiment depicted in thedrawings, it sags into the channel between walls 13 and 13 and creates ablockage therein. This condition, for purposes of this description, isreferred to as involuntary plastic flow. Pressure, aside from theinherent requirement for the plastic, is important in that it must besufficient to compress any air entrapped behind the stretching portionof the parison sufficiently to allow the necessary stretching andbreaking. lt will be apparent that optimum conditions can readily bedetermined empirically for any specific structure being prepared.

Employing the principles described hereinabove with respect to thebottle pump, it is possible to form other structures havingcommunication between their interior and the exterior environmentwithout the necessity of drilling holes and welding the communicatingmembers after the container is formed. FIG. 7 depicts in cutaway ablow-molded container having a breather tube 62 integrally moldedtherewith so that its contents can be poured smoothly. FIG. 8 depicts asqueeze bottle 65 having a suitably bent discharge tube 66 integrallymolded therewith. FlG. 9 depicts a blow-molded container such as, e.g.,a carboy, having a valve assembly 72 and a pouring spout 74 integrallymolded therewith.

Each of the structures depicted in FIGS. 7, 8 and 9 is fabricated usingthe same techniques and the same process considerations as are requiredin forming the bottle described previously. That is to say, a previouslyprepared channel defining member is inserted into a mold and thecontainer is blow-molded into contact therewith. In each case the insertcan, and preferably will, have an exterior flat surface analogous to thechannel support member 12 of the bottle described hereinabove whichbecomes a part of the exterior container wall as does the channelsupport member 12. In any of these embodiments, the same considerationsrelating to the size of the opening as it relates to the temperature,pressure and polymer identity apply. For any structure desired, theseinterrelationships can readily be determined empirically.

What I claim and desire to protect by Letters Patent l. A blow moldedthermoplastic container comprising integral bottom, top and side walls,and an elongated fluid transfer member embedded in a vertical positionin a side wall, said member including an elongated vertical flat portionhaving a pair of substantially parallel elongated ridges projectingtherefrom toward said side wall, said ridges being spaced apart andpositioned in abutting relationship to said side wall to form anenclosed vertical passageway, the top of said passageway being incommunication with the exterior environment, the bottoms of each ridgebeing enlarged and flared inwardly toward the side wall and having anarched portion interconnecting the ridges to define an enlarged taperedinlet chamber, the side wall of said container extending at leastpartially into the inlet chamber and having an opening therein wherebythe interior of the container is in communication with the verticalpassageway.

2. A container as recited in claim 1 wherein the fluid transfer passageis an elongated channel extending to substantially the bottom of thecontainer and having its inlet opening located at its lower extremity.

3. A container as recited in claim 2 including a manually operatedpumping means adapted to remove fluid from the container via the fluidtransfer passage.

1. A blow molded thermoplastic container comprising integral bottom, topand side walls, and an elongated fluid transfer member embedded in avertical position in a side wall, said member including an elongatedvertical flat portion having a pair of substantially parallel elongatedridges projecting therefrom toward said side wall, said ridges beingspaced apart and positioned in abutting relationship to said side wallto form an enclosed vertical passageway, the top of said passagewaybeing in communication with the exterior environment, the bottoms ofeach ridge being enlarged and flared inwardly toward the side wall andhaving an arched portion interconnecting the ridges to define anenlarged tapered inlet chamber, the side wall of said containerextending at least partially into the inlet chamber and having anopening therein whereby the interior of the container is incommunication with the vertical passageway.
 2. A container as recited inclaim 1 wherein the fluid transfer passage is an elongated channelextending to substantially the bottom of the container and having itsinlet opening located at its lower extremity.
 3. A container as recitedin claim 2 including a manually operated pumping means adapted to removefluid from the container via the fluid transfer passage.